在Java中获得具有不同RGB值的相同颜色

Question

I am using jxl to read an Excel file. I need to make a decision, based on font color of a cell. The font color of the cell, I am getting is black, but the RGB value is (1, 0, 0).

When I compare it with Colour.BLACK it fails the == comparison because the RGB value of Colour.BLACK is (0,0,0).

Colour color = nameCell.getCellFormat().getFont().getColour();
if(color == Colour.BLACK) //fails this test 
     options = "0";
else
     options = "1";

In the above code color.getDescription() gives black color in description.

How shall I find that "black" is common in both objects Colour.BLACK and nameCell.getCellFormat().getFont().getColour() ?

Answer 1

You need a way to compare colors in Java.

You could find relevant information here: how could i compare colors in java?

Anyway:

1. You need to compare for equality, not identity so: color == Color.BLACK must translate to Color.BLACK.equals(color)

2. Since you need to compare approximately, you need a way to compute the distance between colors and force it to be under a (experimentally determined) value.

Here is an example:

 public static double distance (Color c1, Color c2){
   double deltaRed=Math.pow((c1.getRed()-c2.getRed())/255.0,2.0);
   double deltaBlue=Math.pow((c1.getBlue()-c2.getBlue())/255.0,2.0);
   double deltaGreen=Math.pow((c1.getGreen()-c2.getGreen())/255.0,2.0);
   double total=Math.sqrt((deltaRed+deltaBlue+deltaGreen)/3.0);
   return total;
 }

 Color color  = nameCell.getCellFormat().getFont().getColor();
 if(distance(color,Color.BLACK) < 0.02)
     options = "0";
 else
     options = "1";    

Answer 2

rgb(1,0,0) is a very dark grey!

Try

if (r <2 && g < 2 && b < 2) ....